Bovine seminalplasmin [corrected] is a DNA unwinding protein

The duplex DNA unwinding ability of seminalplasmin [corrected] from bovine semen was examined by treatment of plasmid-protein complexes with calf thymus topoisomerase I and resolution of the topoisomer distributions by agarose gel electrophoresis. Binding of seminalplasmin [corrected] results in a moderate degree of unwinding of supercoiled plasmid. The elongation of the RNA chain by E. coli RNA polymerase over promoter containing template is not inhibited by seminalplasmin [corrected]. However, the reinitiation of transcription is blocked in such cases indicating that seminalplasmin [corrected] inhibits transcription by binding to the initiation site of RNA polymerase.